Browsing by Issue Date, starting with "1996-12-12"

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The development of a DSP-based active small amplitude vibration control system for flexible beams by using the LQG algorithms and intelligent materials
(1996-12-12)
Bai, MR
;
Lin, GM
;
交大名義發表
;
機械工程學系
;
National Chiao Tung University
An active vibration control system is proposed for suppressing the small amplitude random vibrations in flexible beams. Intelligent materials such as the piezoelectric ceramic PZT are used as the actuator and the piezoelectric plastic PVDF is used as the sensor. The characteristics of the physical system are identified by a parametric modelling technique. The linear quadratic Gaussian (LQG) algorithm is employed for the controller design. The controller is implemented on the basis of a floating-point digital signal processor. The experimental results obtained by using the active vibration control system show significant attenuation of white noise disturbance in the frequency range of approximately 100-800 Hz. (C) 1996 Academic Press Limited
The development of a DSP-based active small amplitude vibration control system for flexible beams by using the LQG algorithms and intelligent materials
(1996-12-12)
Bai, MR
;
Lin, GM
;
機械工程學系
;
Department of Mechanical Engineering
An active vibration control system is proposed for suppressing the small amplitude random vibrations in flexible beams. Intelligent materials such as the piezoelectric ceramic PZT are used as the actuator and the piezoelectric plastic PVDF is used as the sensor. The characteristics of the physical system are identified by a parametric modelling technique. The linear quadratic Gaussian (LQG) algorithm is employed for the controller design. The controller is implemented on the basis of a floating-point digital signal processor. The experimental results obtained by using the active vibration control system show significant attenuation of white noise disturbance in the frequency range of approximately 100-800 Hz. (C) 1996 Academic Press Limited
Bipolaron-induced third-order optical nonlinearity in conjugated conducting polymers
(1996-12-15)
Lai, CM
;
Meng, HF
;
電子物理學系
;
物理研究所
;
Department of Electrophysics
A mechanism, due to the presence of bipolarons, for large resonant chi((3)) in doped cis-polyacetylene and other conjugated conducting polymers is presented. Under optical pumping, the electronic occupations of the two intragap energy levels of the bipolarons will vary, resulting in a shift in their energies, which in turn causes a dramatic change in the absorption spectrum. Even for moderate doping concentrations of bipolarons, chi((3)) is found to be as high as 10(-8) esu.
Bipolaron-induced third-order optical nonlinearity in conjugated conducting polymers
(1996-12-15)
Lai, CM
;
Meng, HF
;
電子物理學系
;
物理研究所
;
Department of Electrophysics
A mechanism, due to the presence of bipolarons, for large resonant chi((3)) in doped cis-polyacetylene and other conjugated conducting polymers is presented. Under optical pumping, the electronic occupations of the two intragap energy levels of the bipolarons will vary, resulting in a shift in their energies, which in turn causes a dramatic change in the absorption spectrum. Even for moderate doping concentrations of bipolarons, chi((3)) is found to be as high as 10(-8) esu.
Enhanced electron emission from phosphorous- and boron-doped diamond-clad Si field emitter arrays
(1996-12-15)
Ku, TK
;
Chen, SH
;
Yang, CD
;
She, NJ
;
Tarntair, FG
A new fabrication technology of polycrystalline diamond-clad Si microtips using microwave plasma chemical vapor deposition (MPCVD) has been developed to improve the characteristics of electron field emission from the pure Si tips. A uniform and smooth coating morphology for the diamond-clad Si tips have been achieved. Electron emission currents of diamond-clad tips are much higher than those of pure Si tips. Such great improvement is attributed to the lowering of the effective work function in the diamond-clad tips. The effects of phosphorus- and boron-doped diamond-clad Si tips have been also studied in comparison with the undoped ones. The current-voltage characteristics of the undoped diamond-clad tips were further enhanced by the in-situ doping of phosphorus or boron due to a higher electron supplement. Moreover, the P-doped diamond-clad tips show a better field emission performance as compared to the B-doped ones. This difference is surmised to be associated with the higher electron conductivity and defect densities of P-doped diamond films.
管管作品三首
(1996-12-15)
管管
Coverage-dependent thermal reactions of digermane on Si(100)-(2x1)
(1996-12-15)
Lin, DS
;
Huang, KH
;
Pi, TW
;
Wu, RT
;
物理研究所
In this study, we examine the adsorption and thermal reactions of digermane (Ge6H6) on the Si(100)-(2X1) surface with high-resolution core-level photoemission spectroscopy using synchrotron radiation. At 325 K, the digermane dissociatively chemisorbed to produce GeH3, GeH2, GeH, and SiH species. The sticking coefficient at zero coverage deduced from the photoemission intensity is similar to 0.5. Successive annealing of rhc digermane-saturated surface tc, higher temperatures causes further decomposition of GeH3 and GeH2 and the desorption H from GeH and SiH, leaving atomic Ge on the surface. In light of the sufficiently large chemical and surface shifts in their core-level binding energies fur different surface species, those processes were identified by examining the evolution of Ge 3d and Si 2p line shapes. Experimental results indicate that the reaction for H release from GeH not only occurred in a large temperature range but also depended heavily on the Ge2H6 adsorption coverages. To reaction routes for H release from Ge sites were used to describe the large reaction temperature spreads accurately. GeH decomposition by transferring the H atom to a surface Si dangling bond took place for low coverages at less than or equal to 590K, and H-2 thermal desorption occurred for higher coverages in the range of 590-770 K. The former process of atom transfer of H from Ge to Si sites was directiy observed in the Ge 3d and Si 2p photoemission spectra.
Effects of mechanical characteristics on the chemical-mechanical polishing of dielectric thin films
(1996-12-15)
Tseng, WT
;
Liu, CW
;
Dai, BT
;
Yeh, CF
;
電子工程學系及電子研究所
The effects of as-deposited (intrinsic) stress, externally applied (extrinsic) stresses, hardness, and modulus of various dielectric firms on chemical-mechanical polishing (CMP) removal and post-CMP cleaning processes are studied in this article. Intrinsic stresses of the polished dielectrics do not contribute directly to the CMP removal rate. Extrinsic stresses including normal and shear components are calculated using principles of elasticity and fluid mechanics respectively and their roles in the material removal process are discussed. Theoretical evaluation and experimental results both suggest that hardness and modulus are the two most important material characteristics affecting the CMP process. Efficiency of post-CMP particle extraction can be monitored using an adhesion probability which is related to the hardness of wafer and pad. Tn addition, particle removal rate can be remarkably enhanced by increasing pressure (normal stress) while increasing pad rotation speed (shear stress) contributes little to reduce the particle count.
管管作品三首
(1996-12-15)
管管
管管作品三首
(1996-12-15)
管管
Origins of the residual stress in CVD diamond films
(1996-12-15)
Kuo, CT
;
Lin, CR
;
Lien, HM
;
交大名義發表
;
材料科學與工程學系
Diamond films were deposited on (100) Si wafer, WC (5%Co) and quartz substrate materials by a microwave plasma chemical vapor deposition (CVD) system. The effects of deposition and substrate conditions on residual stress of the films were systematically investigated The films were characterized by scanning electron microscopy, X-ray diffraction, Raman and indentation adhesion testing. The him structure including its non-diamond carbon content, crystal size, texture coefficient, film thickness and surface roughness were examined. The results show that the residual stress of the films is a function of the surface pretreatment, in addition to the substrate material and deposition conditions. The origins of the residual stress are mainly the thermal stress and the intrinsic stress. The intrinsic stress is mainly from the effect of the non-diamond carbon content in the diamond crystals, not at the crystal boundaries. A greater non-diamond carbon content in diamond crystals results in a greater residual stress. The texture of the films has no significant effect on the residual stress. A low compressive residual stress on Si wafer is beneficial to the adhesion of the film.
管管作品三首
(1996-12-15)
管管
余秋雨刮起文化旋風
(1996-12-22)
陳文芳
Excitonic nonlinearities of semiconductor microcavities in the nonperturbative regime
(1996-12-23)
Jahnke, F
;
Kira, M
;
Koch, SW
;
Khitrova, G
;
Lindmark, EK
A microscopic theory for excitonic nonlinearities and light propagation in semiconductor microcavities is applied to study normal-mode coupling (NMC) for varying electron-hole-pair densities. The nonlinear susceptibility of quantum confined excitons is determined from quantum kinetic equations including dephasing due to carrier-carrier and polarization scattering. The predicted disappearing of the normal-mode transmission peaks with negligible change in the NMC splitting agrees well with cw pump-probe measurements on samples showing remarkable splitting-to-linewidth ratios.
Excitonic nonlinearities of semiconductor microcavities in the nonperturbative regime
(1996-12-23)
Jahnke, F
;
Kira, M
;
Koch, SW
;
Khitrova, G
;
Lindmark, EK
A microscopic theory for excitonic nonlinearities and light propagation in semiconductor microcavities is applied to study normal-mode coupling (NMC) for varying electron-hole-pair densities. The nonlinear susceptibility of quantum confined excitons is determined from quantum kinetic equations including dephasing due to carrier-carrier and polarization scattering. The predicted disappearing of the normal-mode transmission peaks with negligible change in the NMC splitting agrees well with cw pump-probe measurements on samples showing remarkable splitting-to-linewidth ratios.
Coulomb trajectory effects on electron-impact detachment of negative ions and on mutual neutralization cross sections
(1996-12-28)
Lin, JT
;
Jiang, TF
;
Lin, CD
;
電子物理學系
;
物理研究所
Cross sections of electron-impact detachment of negative ions and of mutual neutralization between positive and negative ions are calculated using a model based on the semiclassical theory for ion-atom collisions but modified to include Coulomb trajectory effects. It is shown that the method allows us to obtain accurate results for collisions down to low energies. The Coulomb repulsion between the electron and the negative ion accounts for the rapid decrease of detachment cross sections at low energies, and the Coulomb attraction between positive and negative ions accounts for the rapid increase of neutralization cross sections at low velocities.
應用於衛星通訊系統之加密與解密技術之研究
(1997)
謝續平
;
蘇育德
;
SHIEH SHIUH-PYNG
;
SU YU TED
;
交通大學資訊工程系
總體經濟因素和股價關聯性之分析和預測---主成分迴歸、模糊迴歸及STEIN估計式
(1997)
謝國文
;
Shieh Gwowen
;
交通大學管理科學系
宜蘭縣政府環境規劃案（1995-97）
(1997)
不詳
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New transmission line systems for accumulating power from distributed renewable energy
(1997-01-01)
Kuo, MY
;
Kuo, CC
;
Kuo, MS
;
交大名義發表
;
電子工程學系及電子研究所